1. Field of the Invention
The present invention relates to a control device for a link mechanism including one or more joint mechanisms disposed between a base body and a movable part which is movable relative to the base body and an actuator which outputs a driving force for displacing the one or more joint mechanisms, wherein each of the one or more joint mechanisms is adapted to transmit motive power via an elastically-deformable elastic element whose stiffness is variably controllable.
2. Description of the Related Art
Conventionally, there is known a control device for a link mechanism including a plurality of joint mechanisms disposed between a base body and a movable part which is movable relative to the base body and an actuator which outputs a driving force for displacing the plurality of joint mechanisms, wherein each of the plurality of joint mechanisms is adapted to transmit motive power via an elastically-deformable elastic element whose stiffness is variably controllable (Japanese Patent Application Laid-Open No. 2008-302496). The control device for the link mechanism controls the stiffness of the elastic elements of joint mechanisms on the side closer to the base body than the movable part to be smaller than the stiffness of the elastic elements of other joint mechanisms when the movable part collides with an external object.
In the control device for the link mechanism as described in Japanese Patent Application Laid-Open No. 2008-302496, however, the stiffness of the elastic element of each joint mechanism is controlled without considering the kinetic energy or the like of each joint mechanism generated by a collision of the movable part against the object. Consequently, in each joint mechanism, a load larger than a load allowable for the joint mechanism acts on the joint mechanism when the movable part collides with the object, which might damage the joint mechanism.
The present invention has been provided in view of the above problem. Therefore, it is an object of the present invention to provide a control device for a link mechanism including one or more joint mechanisms disposed between a base body and a movable part which is movable relative to the base body and an actuator which outputs a driving force for displacing the one or more joint mechanisms, wherein each of the one or more joint mechanisms is adapted to transmit motive power via an elastically-deformable elastic element whose stiffness is variably controllable, the control device capable of preventing the joint mechanisms from being damaged even in the case where the movable part collides with an external object.